In a default installation, all components of the EASA system are installed to a single EASA Server. In addition to the possibility of configuring remote compute and Excel servers, it is possible to configure one or more Web Browser Client servers separately from the EASA server. This may be a preferable solution in cases where EASA is deployed to a large number of users. With multiple Web Browser Client servers in operation, the EASA system features load balancing technology which is able to detect and select the server with the most available resources to provide Web Browser Client access to a user at any given time. This process is automatic and requires no input from the user.

Like compute server configuration, this functionality brings with it a broad range of configuration options. Depending on the needs of your organization, you may wish to add a single supporting Web Browser Client server to your main EASA Server, or you may wish to configure multiple Web Browser Client servers while relieving the main EASA Server of this role altogether.

Configuration of an EASA cluster installation involves the addition of extra EASA servers to handle Web Browser Client load. These additional servers do not require a full EASA installation, only a partial installation through use of advanced mode in the EASA installer. In the following example scenario, we will configure a cluster with a main EASA server, and two Web Browser Client servers. Users will only need to directly access the main EASA server. Upon the launch of an EASAP, their browsers will be directed to one of the two Web Browser Client servers, depending on their available resources. The following example steps assume that you are performing a fresh EASA installation on your main server. This would be the preferred method, since we are able to omit certain components from the main server, thereby maximizing available resources. This cluster installation example will consist of four stages:

• Installing a main EASA Server configuration on the EASA Server
• Installing a partial EASA Server configuration on the two Web Browser Client servers
• Configuring the Web Browser Client servers to support the main EASA Server
• Configuring the main EASA Server to use the Web Browser Client servers

Setup steps for EASA Server are described at Installation of EASA Software. When the Select Installation Type window appears, you should choose an Advanced Installation. In this example scenario, we will choose not to install the “Web Browser Access” component, as this refers to the Web Browser Client service. An example of the Select Components interface is shown below.

Once the necessary components have been selected, proceed through the rest of the installation.

On the Web Browser Client servers, we will also perform an advanced installation. For a dedicated Web Browser Client server, just two components are required. These are Web Browser Access, and Spreadsheet Support. Please note that Spreadsheet Support is necessary in order to run EASAPs with Spreadsheet components, even though these servers will not function as Excel servers. An example of the Select Components interface for a Web Browser Client server is shown below.

Since our Web Browser Client servers will not feature an EASA Server component, they will require the address of the main EASA Server for correct operation. You will be prompted to enter the URL of the main EASA Server at the EASA server URL prompt during installation.

Note: If your Main EASA Server runs on a port other than 80, you need to specify the port in this URL. For example: http://EASASERVER:8080/easa

Repeat this installation process on all Web Browser Client servers (two in the case of this example scenario).

If a remote JSF server is to be used with EASA, some manual configuration is necessary to make the server work in order. Specifically, two lines must be edited in the context.properties file as follows:

The hash (#) characters must be removed from the beginning of the following lines

 #easa.server.public=http://127.0.0.1/easa
 
 #easa.server.private=http://127.0.0.1/easa
 
 #jsf.public.url=http://127.0.0.1/jsf-easa

and 127.0.0.1 should be replaced with the machine name or static IP address of the server machine. After editing they should look similar to the following:

 easa.server.public=http://<name or IP of EASA server machine>/easa
 
 easa.server.private=http://<name or IP of EASA server machine>/easa
 
 jsf.public.url=http://<name or IP of JSF server machine>/jsf-easa

If the port used by the server is different than the default value of 80, it must be included in the machine name or static IP as well after a semicolon.

For example, if the machine name of the remote JSF server is “EASA_remote_JSF”, the machine name of the EASA server is “EASA_Server” and the port used is 8080 in both cases, the above lines should look like:

 easa.server.public=http://EASA_Server:8080/easa
 
 easa.server.private=http://EASA_Server:8080/easa
 
 jsf.public.url=http://EASA_remote_JSF:8080/jsf-easa

The context.properties file that needs to be edited is found in the

 <EASAROOT>/webapps/jsf-easa/admin/custom_config

folder.

In addition to the two lines above, another line needs to be edited in order to enable remote JSF functionality.

In case of a fresh installation of EASA 5.2.2 or later version, the hash character at the beginning of the following line has to be removed in the context.properties file:

   #easa.jsf.remote=true

If an existing installation is upgraded to 5.2.2 or later, the above line is not present and needs to be added as follows:

   easa.jsf.remote=true

Note: In this case, whether an installation is “fresh” or an “upgrade” is determined by if a new EASAServerData folder is created or an existing one is used.

EASA installations with multiple JSF servers and multiple Excel servers are handled by the built in EASA Load Balancer. This will take many factors into account when loading, running and submitting EASAPs, like Excel server types, number of available processes of each type, number of available system memory on a particular machine and so on.

Since a server model similar to that might not be a typical installation, this is not assumed as the default setting by EASA and there fore additional configuration is necessary.

Each remote JSF server running an Excel server on the same machine needs to be “coupled”, assigned to each other for exclusive use, for the load balancer to work as intended. What this means is by setting the correct property on each remote server machine, JSF servers will consider their local Excel installations for use. This benefits both stability and performance.

To set the property on each server machine, go to the file system, navigate to \<EASA Server Data folder>\jsf-easa\admin\config\ and edit the context.properties file, removing the # character from the beginning of the following line:

   #excel.provider=local

Save the file, exit and restart the service.

Note: Remote JSF servers cannot be used with a local Excel server. As a result, if a remote JSF server is used, a coupled remote Excel server must be used as well.

By now, all of the servers should be configured correctly. You can check that the Web Browser Client servers are functional by opening a Web Browser Client based EASAP from your main EASA Server. If the configuration is working properly, you should see the name of a Web Browser Client server in the address bar on the EASAP.

From now on, Web Browser Client EASAPs will open on one of the Web Browser Client servers. If you have chosen to configure multiple Web Browser Client servers with similar hardware specifications, you may be able to test and see the load balancing technology by opening a large number of EASAPs simultaneously.